Interface effect on mn-containing self-formed barrier formation with extreme low-k dielectric integration

The combination of self-formed barrier (SFB) and extreme low-k (ELK) dielectric is an attractive candidate for interconnect integration beyond 28nm-node regarding to low RC delay and Cu filling. Attempt is made to understand the formation mechanism of SFB through combinations with various ELK dielectrics in this study. In terms of wiring and dielectric reliabilities, the combination of Mn_xO_y SFB and ELK with the lowest k value in this study could have the best reliability results if a suitable patterning approach is selected. Furthermore, the property requirements for interface on which SFB will form are studied by an additional thin CVD dielectric liner deposited on the patterned ELK dual-damascene structure. It is found that the suitable interface for SFB formation with high corrosion resistance and robust electro-migration (EM) performance would need higher carbon content and the existence of nitrogen.